Multiple linear gradient maker

ABSTRACT

A multiple linear gradient maker includes a block of acrylic plastic having three pairs of conical chambers with the inner chambers being for the dense solution and the outer chamber for the less dense solution. Paddlelike stirrers are immersed in the solution in the inner chambers. A rotatable valve plate is mounted on the larger block to normally close off the lower openings of the chambers in a first position but when moved to a second position provides fluid communication channels between the chamber pairs. Outlet channels are also located adjacent the fluid communication channels to drain the fluid into test tubes.

United States H man,

[72) Inventor [54] MULTRPLE LllNlEAlR GRADIENT MAKER OTHER REFERENCES Variable Gradient Device for Chromatography," by

Peterson and Sober, pub in Analytical Chemistry," vol. 31, No. 5, May 1959. Copy in Group 170.

Primary Examiner-William 1. Price Assistant Examiner-Philip R. Coe Attorney-Flehr, Hohbach, Test, Albritton & Herbert ABSTRACT: A multiple linear gradient maker includes a block of acrylic plastic having three pairs of conical chambers with the inner chambers being for the dense solution and the outer chamber for the less dense solution. Paddlelike stirrers are immersed in the solution in the inner chambers. A rotata ble valve plate is mounted on the larger block to normally close off the lower openings of the chambers in a first position but when moved to a second position provides fluid communication channels between the chamber pairs. Outlet channels are also located adjacent the fluid communication channels to drain the fluid into test tubes.

*Patented 3, 1971 2 Sheets-Sheet l mm mm: C

INVENTOR. PETER S. HOEFER 2M W 'M, m M

ATTORN EYS Patented Aug. 3, 1911 2 Sheets-Sheet B INVENTOR. PETER S. HOEFER FIG-3 ATTORNEYS MULTIPLE LINEAR GRADIENT MAKER BACKGROUND OF THE INVENTION The present invention is directed to a multiple linear gradient maker and more particularly a gradient maker for sucrose.

In general, linear gradient makers have at least a pair of chambers. One of the chambers holds a dense solution of sucrose, for example, and the other chamber a less dense solution. The two chambers are coupled together and an outlet channel provided from the dense solution chamber. As the solution starts to drain into a test tube from the dense solution chamber the initial solution which is allowed to drain into the test tube will be of substantially the density of the dense solution chamber. As the process continues, the solution deposited in the test tube becomes less dense approaching the density of the less dense solution. This occurs in a linear manner.

Prior gradient makers when arranged for the production of multiple gradients have required complex hookups and associated mechanism. For example, one type uses a motor driven cam to drive at a controlled rate three pairs of syringe barrels into three pairs of mixing chambers. In another type a single chamber pair is used in which one chamber has three outlets. Since gravity feed alone will not assure three gradients of equal volume a three-channel tubing pump is used to pump out the contents in three equal volumes.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, a general object of the invention to provide an improved gradient maker.

' It is another object of the invention to provide a multiple linear gradient maker which is simple in construction and provides multiple gradients of equal volume.

In accordance with the above objects there is provided a multiple linear gradient maker having a pair of chambers one of such chambers of the pair holding a dense solution and the other a less dense solution. The maker comprises a unitary block having a plurality of pairs of chambers bored through such block in a predetermined common direction each of the chambers having first and second openings. The chambers are adapted for receiving the solution at the first opening. The second openings lie in a single plane. Means having a first position for closing the second openings and having a second position provide for communication between the chamber pairs. Such means include a unitary block rotatable between the two positions and having a flat surface and means for maintaining the flat surface in continuous engagement with the second openings. A plurality of channel means in the rotatable block correspond to the plurality of chamber pairs for coupling pairs of the second openings when the block is in the second position for allowing solution to flow from one chamber of a pair to the other. A plurality of outlet channel means corresponding to the plurality of chamber pairs are included in the rotatable block for draining solution from one of the chambers of a pair when the block is in the second position. Means are provided for rotating the rotatable block between its two positions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a gradient maker incorporating the present invention;

FIG. 2 is an enlarged cross-sectional view taken along line 2-2 ofFIG. 1; and

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. l, a unitary tilock 11 is provided with a plurality of pairs of chambers 12a, 12b and 120 bored through block 111 in an axial direction. More specifically, block 11 is in the form of a relatively thick disc and chambers 12ac in the form of truncated cones having their axes parallel with a central axis 16 of block 11. Each chamber pair consists of an inner chamber 12'a--c and an outer chamber 12"ac. The six chambers have their axes on an equilateral triangle in which there is an outer chamber at each apex and an inner chamber midway on each side. Representative chambers are best shown in FIG. 2.

Each chamber has a first opening 13a-c for receiving either the dense sucrose solution or the less dense sucrose solution and a second opening Ma-c at the other side of block 11. Second openings 14a--c all lie in a single plane. Block llll is mounted on cylindrical legs 15ac which are embedded in the block.

Means are provided for closing second openings Ma-c or alternatively providing for communication via these openings between the individual chamber pairs 12a, 12b and 120. Such means include a unitary block or relatively thin disc or plate 17 which is rotatable by a lever 18 between a first position which closes the openings of chambers 12a-c and a second position as illustrated which provides communication between the individual chamber pairs. Such second position is indexed by a stud 19 embedded in block 11 and the first position by a stud 21.

Valve plate 17 has a flat upper surface 22 which is maintained against the single plane formed by the openings Ma-c by a collar 20 affixed to block 11 by a fastener 23 located along axis 16. Plate 17 is allowed to rotate about axis 16 against the friction force produced by collar 20. Thus, the flat surface 22 is maintained in continuous engagement with the second chamber openings I la-c.

As best illustrated in FIG. 3, a plurality of channel means or ducts 24a-c are in rotatable plate 17 to provide communication between corresponding chamber pairs 12a-c respectively. Valve plate 17 is in its second position as illustrated. Each coupling duct includes a horizontal portion and vertical portions 2511-0 and 26a-c at each end for communicating with the individual openings of the chamber pairs with which the duct is associated. The horizontal portion of each duct is bored into plate 17 and then plugged by plugs 27ac respectively. Vertical portions 25a--c as best shown in FIG. 3 are in juxtaposition with second openings 14a--c of the inner chambers.

A plurality of outlet channel means 30a-c corresponding to chamber pairs 12a-c are also included in rotatable plate 117 for draining solution from the inner chambers when the block is in its second position as illustrated. Such outlet channel means include as best illustrated in FIG. 2 a narrow tube portion 31a juxtaposed with opening 14a in the case of channel pair 12a and an enlarged portion 320 which extends to the other side of plate 17. Force fitted into enlarged portion 32a is a threaded plastic bushing 33a. A plastic tube 34a is retained in abutment with the threaded bushing by a metal female threaded retainer ring 36a. Tube 34a has mounted on it an adjustable valve 37a having a head portion 38a, a threaded stud portion 39a through which tube 34a extends and a nut 40a. Adjustment of the nut controls the rate: of flow of the solution from the chamber.

In order to provide a seal between plate 17 and block 11, 0- rings 42a-c are provided coaxial with the second openings Mia-c of the chamber pairs. The O-rings are in sliding contact with valve plate 17. Such O-rings: are, however, spaced from the opening by a rim of the material of which block 11 is made.

Block 11, valve plate 17, bushings 33a-c and tubes 34ac are all constructed of acrylic plastic. Thus, no metals come into contact with the solution. The only metal portions are female fastener Boa-c and the various handles and legs. In addition, the O-rings 42a-c, which would normally be of a rubber-type material, have very limited contact if any with the solution since they are spaced from the openings 14ac by the rim of the plastic material of the block 11.

Means for stirring the solution in the inner chambers l2'a, l2'b and 12'c are illustrated in FIG. 1 and include paddlelike members 43a-c corresponding to chamber pairs l2a-c coupled to gear train 44 which in turn is driven by motor 46 which may be connected to a source of standard household voltage by plug 47. Paddles 43ac are driven at 1,000 rpm. and in addition to mixing the two types of solutions produce a lifting effect to prevent the denser, heavier solution flowing into the outer chamber containing the lighter solution. It has been found that the above paddle speed is optimum within :300 rpm. Guides 48 extending downwardly are adapted for insertion into holes 49 in block 11.

The paddles 43a-c are immersed in the solution in the three inner chambers and the motor 46 actuated. At this time lever 18 is moved from its position against stud 21 closing the openings l4a-c of the chambers into its second position against stud 19 as illustrated. Each valve 37a-c can then be adjusted individually to control the outflow rate from each of the inner chambers into the collecting test tubes. A typical test tube 50 (one of three) is shown mounted in an L-shaped stand 51 with the tube being held by a perimeter spring 52. The stand is fixed to a platform 53 slidably mounted by leg b to accommodate difierent sized test tubes.

Thus, an improved linear gradient maker has been provided which makes three separate gradients of equal volume at the same time in the same unit. More particularly gravity feed alone produces the three equal volumes. The three pairs of chambers are connected at once by the single lever to provide mechanically trouble-free operation. The chambers themselves while ideally truncated cones to give greater height for better mixing may be in the shape of a funnel or a narrow cylinder. The single vibrator produces stirring at equal rates in each of the three inner chambers.

I claim:

1. A multiple linear gradient maker of the type having a pair of chambers one of such chambers of said pair adapted for holding a dense solution and the other a less dense solution comprising; a unitary block having a plurality of pairs of chambers bored through said block in a predetermined common direction each of said chambers having first and second openings said chambers being adapted for receiving said solutions at said first opening, said second openings lying in a single plane; means having a first position for closing said second openings and having a second position for providing communication between said chamber pairs such means including, a unitary block rotatable between said tow positions and having a flat surface, means for maintaining said flat surface in continuous engagement with said second openings, a plurality of channel means in said rotatable block corresponding to said plurality of chamber pairs for coupling pairs of said second openings when said block is in said second position for allowing solution to flow from one chamber of a pair to the other, a plurality of outlet channel means corresponding to said plurality of chamber pairs included in said rotatable block for draining solution from one of said chambers of a pair when said block is in said second position, and means for rotating said rotatable block between said two positions.

2. A multiple linear gradient maker as in claim 1 where said outlet channel means are in close proximity to corresponding coupling channel means.

3. A multiple linear gradient maker as in claim 1 where said outlet channel means are juxtaposed with said second openings when said rotatable block is in said second position.

4. A multiple linear gradient maker as in claim 1 including means for stirring inserted in only one of said chambers per pair.

5. A multiple linear gradient maker as in claim 4 where said stirring means are inserted in said chambers adapted for holding said dense solution.

6. A multiple linear gradient maker as in claim 4 where said chambers are truncated cones and where said stirring means includes paddlelike means together with means for rotating said paddlelike means to provide a vortex type of stirring acti n.

7. A multiple linear gradient maker as in claim 6 where said paddlelike means are rotated at a speed of substantially 1,000 revolutions per minute.

8. A multiple linear gradient maker as in claim 1 together with O-rings coaxial with said second openings for providing a seal between such openings and said flat surface of said rotatable block.

9. A multiple linear gradient maker as in claim 1 where said outlet channel means include individual valve means for adjusting the rate of flow of solution therefrom.

10. A multiple linear gradient maker as in claim 1 where said chambers are truncated cones.

11. A multiple linear gradient maker as in claim 1 in which there are three pairs of chambers the axes of said chambers lying on an equilaterial triangle in which there is one chamber of each pair at each apex and the other chamber of each pair midway on each side. 

1. A multiple linear gradient maker of the type having a pair of chambers one of such chambers of said pair adapted for holding a dense solution and the other a less dense solution comprising: a unitary block having a plurality of pairs of chambers bored through said block in a predetermined common direction each of said chambers having first and second openings said chambers being adapted for receiving said solutions at said first opening, said second openings lying in a single plane; means having a first position for closing said second openings and having a second position for providing communication between said chamber pairs such means including, a unitary block rotatable between said tow positions and having a flat surface, means for maintaining said flat surface in continuous engagement with said second openings, a plurality of channel means in said rotatable block corresponding to said plurality of chamber pairs for coupling pairs of said second openings when said block is in said second position for allowing solution to flow from one chamber of a pair to the other, a plurality of outlet channel means corresponding to said plurality of chamber pairs included in said rotatable block for draining solution from one of said chambers of a pair when said block is in said second position, and means for rotating said rotatable block between said two positions.
 2. A multiple linear gradient maker as in claim 1 where said outlet channel means are in close proximity to corresponding coupling channel means.
 3. A multiple linear gradient maker as in claim 1 where said outlet channel means are juxtaposed with said second openings when said rotatable block is in said second position.
 4. A multiple linear gradient maker as in claim 1 including means for stirring inserted in only one of said chambers per pair.
 5. A multiple linear gradient maker as in claim 4 where said stirring means are inserted in said chambers adapted for holding said dense solution.
 6. A multiple linear gradient maker as in claim 4 where said chambers are truncated cones and where said stirring means includes paddlelike means together with means for rotating said paddlelike means to provide a vortex type of stirring action.
 7. A multiple linear gradient maker as in claim 6 where said paddlelike means are rotated at a speed of substantially 1,000 revolutions per minute.
 8. A multiple linear gradient maker as in claim 1 together with O-rings coaxial with said second openings for providing a seal between such openings and said flat surface of said rotatable block.
 9. A multiple linear gradient maker as in claim 1 where said outlet channel means include individual valve means for adjusting the rate of flow of solution therefrom.
 10. A multiple linear gradient maker as in claim 1 where said chambers are truncated cones.
 11. A multiple linear gradient maker as in claim 1 in which there are three pairs of chambers the axes of said chambers lying on an equilaterial triangle in which there is one chamber of each pair at each apex and the other chamber of each pair midway on each side. 